Problem: Express this number in scientific notation. $\text{19 hundred-thousandths}$
Solution: $\text{19 hundred-thousandths}$ can be written as $0.00019$ in standard form. Count the zeroes to the right of the decimal point before the leading ${1}$ : there are $3$ zeroes. If you count the leading digit ${1}$, there are ${4}$ digits to the right of the decimal point. So: $\text{19 hundred-thousandths}= {1}.9 \times 10^{{-4}}$